<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
                "http://www.w3.org/TR/REC-html40/loose.dtd">
<html>
<head>
  <title>Description of v_distispf</title>
  <meta name="keywords" content="v_distispf">
  <meta name="description" content="V_DISTISPF calculates the Itakura-Saito spectral distance between power spectra D=(PF1,PF2,MODE)">
  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
  <meta name="generator" content="m2html &copy; 2003 Guillaume Flandin">
  <meta name="robots" content="index, follow">
  <link type="text/css" rel="stylesheet" href="../m2html.css">
</head>
<body>
<a name="_top"></a>
<div><a href="../index.html">Home</a> &gt;  <a href="index.html">v_mfiles</a> &gt; v_distispf.m</div>

<!--<table width="100%"><tr><td align="left"><a href="../index.html"><img alt="<" border="0" src="../left.png">&nbsp;Master index</a></td>
<td align="right"><a href="index.html">Index for v_mfiles&nbsp;<img alt=">" border="0" src="../right.png"></a></td></tr></table>-->

<h1>v_distispf
</h1>

<h2><a name="_name"></a>PURPOSE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="box"><strong>V_DISTISPF calculates the Itakura-Saito spectral distance between power spectra D=(PF1,PF2,MODE)</strong></div>

<h2><a name="_synopsis"></a>SYNOPSIS <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="box"><strong>function d=v_distispf(pf1,pf2,mode) </strong></div>

<h2><a name="_description"></a>DESCRIPTION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="fragment"><pre class="comment">V_DISTISPF calculates the Itakura-Saito spectral distance between power spectra D=(PF1,PF2,MODE)

 Inputs: PF1,PF2     Power spectra to be compared. Each row represents a power spectrum: the first
                     and last columns represent the DC and Nyquist terms respectively.
                     PF1 and PF2 must have the same number of columns.

         MODE        Character string selecting the following options:
                         'x'  Calculate the full distance matrix from every row of PF1 to every row of PF2
                         'd'  Calculate only the distance between corresponding rows of PF1 and PF2
                              The default is 'd' if PF1 and PF2 have the same number of rows otherwise 'x'.
           
 Output: D           If MODE='d' then D is a column vector with the same number of rows as the shorter of PF1 and PF2.
                     If MODE='x' then D is a matrix with the same number of rows as PF1 and the same number of columns as PF2'.

 The Itakura-Saito spectral distance is the average over +ve and -ve frequency of 

                      pf1/pf2 - log(pf1/pf2) - 1     =     exp(v) - v - 1         where v=log(pf1/pf2)

 The Itakura-Saito distance is asymmetric: pf1&gt;pf2 contributes more to the distance than pf2&gt;pf1. 
 A symmetrical version is the COSH distance: v_distchpf(x,y)=(v_distispf(x,y)+v_distispf(y,x))/2</pre></div>

<!-- crossreference -->
<h2><a name="_cross"></a>CROSS-REFERENCE INFORMATION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
This function calls:
<ul style="list-style-image:url(../matlabicon.gif)">
</ul>
This function is called by:
<ul style="list-style-image:url(../matlabicon.gif)">
</ul>
<!-- crossreference -->


<h2><a name="_source"></a>SOURCE CODE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="fragment"><pre>0001 <a name="_sub0" href="#_subfunctions" class="code">function d=v_distispf(pf1,pf2,mode)</a>
0002 <span class="comment">%V_DISTISPF calculates the Itakura-Saito spectral distance between power spectra D=(PF1,PF2,MODE)</span>
0003 <span class="comment">%</span>
0004 <span class="comment">% Inputs: PF1,PF2     Power spectra to be compared. Each row represents a power spectrum: the first</span>
0005 <span class="comment">%                     and last columns represent the DC and Nyquist terms respectively.</span>
0006 <span class="comment">%                     PF1 and PF2 must have the same number of columns.</span>
0007 <span class="comment">%</span>
0008 <span class="comment">%         MODE        Character string selecting the following options:</span>
0009 <span class="comment">%                         'x'  Calculate the full distance matrix from every row of PF1 to every row of PF2</span>
0010 <span class="comment">%                         'd'  Calculate only the distance between corresponding rows of PF1 and PF2</span>
0011 <span class="comment">%                              The default is 'd' if PF1 and PF2 have the same number of rows otherwise 'x'.</span>
0012 <span class="comment">%</span>
0013 <span class="comment">% Output: D           If MODE='d' then D is a column vector with the same number of rows as the shorter of PF1 and PF2.</span>
0014 <span class="comment">%                     If MODE='x' then D is a matrix with the same number of rows as PF1 and the same number of columns as PF2'.</span>
0015 <span class="comment">%</span>
0016 <span class="comment">% The Itakura-Saito spectral distance is the average over +ve and -ve frequency of</span>
0017 <span class="comment">%</span>
0018 <span class="comment">%                      pf1/pf2 - log(pf1/pf2) - 1     =     exp(v) - v - 1         where v=log(pf1/pf2)</span>
0019 <span class="comment">%</span>
0020 <span class="comment">% The Itakura-Saito distance is asymmetric: pf1&gt;pf2 contributes more to the distance than pf2&gt;pf1.</span>
0021 <span class="comment">% A symmetrical version is the COSH distance: v_distchpf(x,y)=(v_distispf(x,y)+v_distispf(y,x))/2</span>
0022 
0023 <span class="comment">% The Itakura-Saito distance can also be calculated directly from AR coefficients; providing np is large</span>
0024 <span class="comment">% enough, the values of d0 and d1 in the following will be very similar:</span>
0025 <span class="comment">%</span>
0026 <span class="comment">%         np=255; d0=v_distisar(ar1,ar2); d1=v_distispf(v_lpcar2pf(ar1,np),v_lpcar2pf(ar2,np))</span>
0027 <span class="comment">%</span>
0028 
0029 <span class="comment">% Ref: A.H.Gray Jr and J.D.Markel, &quot;Distance measures for speech processing&quot;, IEEE ASSP-24(5): 380-391, Oct 1976</span>
0030 <span class="comment">%      L. Rabiner abd B-H Juang, &quot;Fundamentals of Speech Recognition&quot;, Section 4.5, Prentice-Hall 1993, ISBN 0-13-015157-2</span>
0031 <span class="comment">%      F.Itakura &amp; S.Saito, &quot;A statistical method for estimation of speech spectral density and formant frequencies&quot;,</span>
0032 <span class="comment">%                            Electronics &amp; Communications in Japan, 53A: 36-43, 1970.</span>
0033 
0034 
0035 <span class="comment">%      Copyright (C) Mike Brookes 1997</span>
0036 <span class="comment">%      Version: $Id: v_distispf.m 10865 2018-09-21 17:22:45Z dmb $</span>
0037 <span class="comment">%</span>
0038 <span class="comment">%   VOICEBOX is a MATLAB toolbox for speech processing.</span>
0039 <span class="comment">%   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html</span>
0040 <span class="comment">%</span>
0041 <span class="comment">%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%</span>
0042 <span class="comment">%   This program is free software; you can redistribute it and/or modify</span>
0043 <span class="comment">%   it under the terms of the GNU General Public License as published by</span>
0044 <span class="comment">%   the Free Software Foundation; either version 2 of the License, or</span>
0045 <span class="comment">%   (at your option) any later version.</span>
0046 <span class="comment">%</span>
0047 <span class="comment">%   This program is distributed in the hope that it will be useful,</span>
0048 <span class="comment">%   but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
0049 <span class="comment">%   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the</span>
0050 <span class="comment">%   GNU General Public License for more details.</span>
0051 <span class="comment">%</span>
0052 <span class="comment">%   You can obtain a copy of the GNU General Public License from</span>
0053 <span class="comment">%   http://www.gnu.org/copyleft/gpl.html or by writing to</span>
0054 <span class="comment">%   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.</span>
0055 <span class="comment">%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%</span>
0056 
0057 [nf1,p2]=size(pf1);
0058 p1=p2-1;
0059 nf2=size(pf2,1);
0060 <span class="keyword">if</span> nargin&lt;3 | isempty(mode) mode=<span class="string">'0'</span>; <span class="keyword">end</span>
0061 <span class="keyword">if</span> any(mode==<span class="string">'d'</span>) | (mode~=<span class="string">'x'</span> &amp; nf1==nf2)
0062    nx=min(nf1,nf2);
0063    r=pf1(1:nx,:)./pf2(1:nx,:);
0064    q=r-log(r);
0065    d=(sum(q(:,2:p1),2)+0.5*(q(:,1)+q(:,p2)))/p1-1;
0066 <span class="keyword">else</span>
0067    r=permute(pf1(:,:,ones(1,nf2)),[1 3 2])./permute(pf2(:,:,ones(1,nf1)),[3 1 2]);
0068    q=r-log(r);
0069    d=(sum(q(:,:,2:p1),3)+0.5*(q(:,:,1)+q(:,:,p2)))/p1-1;
0070 <span class="keyword">end</span></pre></div>
<hr><address>Generated by <strong><a href="http://www.artefact.tk/software/matlab/m2html/">m2html</a></strong> &copy; 2003</address>
</body>
</html>